I have a dimmer (Richmond/Zano GRID500) that, when turned up to full brightness, dims the lights on and off at a rate of about 1 Hz.
Turning the brightness down just a bit makes the blinking stop.
The switch did this with 6x 50W halogen bulbs, and is continuing to do this with 6x 5W LED bulbs.
Since the blinking looks deliberate, I am wondering if the switch is trying to tell me something? I found some manufacturer's literature, but there's nothing relevant there.